In this paper we describe findings concerning a limited part of teacher behaviour namely relational skills. These skills are of vital importance if a teacher is to create a good classroom atmosphere. On the basis of theories of Leary (1957) and Watzlawick et al. (1968) we have constructed a model that describes relational aspects of teacher behaviour. This model focusses on teacher behaviour as revealed in teacher pupil interactions. These interactions are analysed by means of the system theory of communication. We have investigated teacher behaviour as observed by teachers and pupils, with the help of an instrument called 'The Questionnaire for Interactional Teacher Behaviour'. It is found that from the pupils' point of view good teachers are distinguished from bad teachers by the amount of kindness and understanding they show, their helpfulness and the way they manage a class. We also investigated the behaviour that teachers themselves wish to display. They agree about the need to be kind, helpful and understanding but differ in the amount of strict behaviour they want to display and in the amount of freedom and independence they want to give to pupils. We also investigated with this questionnaire the teacher behaviour of teachers who teach different subjects. It is found that pupils consider modern language teachers in particular to behave differently from other teachers; they are stricter, less kind and give less independence to pupils. This different behaviour of modern language teachers may be due to the structure of the subject matter, or to the way in which languages are taught at universities to future teachers.We think teacher trainers should be concerned with our findings because when teachers, and particularly language teachers, become older they seem to have increasing difficulty in creating and maintaining an adequate relationship with their pupils.